Ion implantation is a technology for doping, wherein a surface of a silicon wafer is bombarded with high-energy ions, and impurity ions go into a silicon body at a doping window, and the other area of the surface of the silicon wafer is masked by a protection layer, thus locally selective doping is accomplished. The ion implantation is a key process step in semiconductor processes, and in the display field and the semiconductor manufacturing field, various semiconductor doping areas can be formed on the semiconductor substrate through ion implantation, this is the basis for forming various device structures.
In ion implantation processes, in order to guarantee the substrate to have the predetermined electrical performances after implanting impurities, there is restrict requirement on a concentration and a depth of the implanted impurities, thus, it is necessary to monitor the ion implantation process in real time. An existing method for monitoring the ion implantation process is as follows: after the ion implantation is completed, a piece to be monitored is firstly annealed accordingly to activate the implanted impurities, then its resistance is measured by a four-probe method, and finally, it is determined whether or not the concentration of the implanted impurities meets the requirement according to the resistance. However, in such a monitoring method, as an intrinsic resistance of the silicon wafer substrate is greatly varied, the final calculation result will be affected greatly thereby, and at the same implantation condition and at the same annealing condition, there will be a great difference between the final test results for silicon wafer substrates with different intrinsic resistances, it is impossible to accurately monitor the resistance of a substrate after ion implantation, and the monitoring result has a poor accuracy.